The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. The system and method relate in general to cable systems and, in particular, to a system and apparatus for preventing the loss of a cable into a wellbore for use in the oilfield services industry.
Cable, typically composed of braided steel wire or the like, is used in a wide range of applications to support a load under tension. An application is in the oilfield services industry, where wireline tools, toolstrings or the like are lowered into a wellbore via a cable that is commonly referred to as wireline cable. The cable is supported and anchored by some other device such as a winch, drum or capstan and is routed from the winch, drum, or capstan, to other locations by sheaves. The cable typically has a finite load that it can support, generally indicated by its safe working load. The load capacity of the cable can decrease for several reasons and failure of the cable may occur if the load capacity is exceeded.
Failure of the cable results in loss of load support, where the cable will then move in a direction towards the load that the cable was supporting and may occur unexpectedly and possibly without warning. Once a failure has occurred, the cable typically accelerates very quickly. This is especially likely if the cable fails by separating into multiple pieces, where the initial tension and stretch of the cable prior to breaking results in storage of potential energy within the cable, which is converted to kinetic energy once the cable is separated. Failure in wireline applications may disadvantageously result in the cable entering the wellbore.
It is desirable, therefore, to provide a system and apparatus for preventing the loss of a cable into a wellbore.